1. Field of the Invention
The present invention relates to telecommunications equipment, and, in particular, to configurations for grounding panels used to mount electrical connectors such as high-voltage/high-current plug-in protectors.
2. Description of the Related Art
High-voltage/high-current plug-in protectors are used in telecommunications applications to provide electrical isolation between telecommunications equipment in a building and the cabling that carries the electrical signals for the telecommunications equipment to and from the building. A typical five-pin plug-in protector has two conducting pins that are connected to telecommunications equipment (e.g., a telephone), two conducting pins that are connected to wiring broken out from the cabling, and a fifth conducting pin that is connected to ground.
During normal operations, a plug-in protector connects the cable-side conductors to corresponding conductors on the equipment side to allow the flow of telecommunications signals between the equipment and the rest of the telecommunications network. In the case of sufficiently high voltage and/or current at one side, e.g., from a lightning strike at the cable side, the plug-in protector connects the cable-side conductors to ground, thereby preventing damage to the equipment and possible injury to a user of that equipment.
In a building, such as an office building, having a large number of telephones and other telecommunications equipment, each of which requires its own pair of wires from a multi-wire cable, a plug-in protector is used for each pair of wires. These plug-in protectors are typically mounted in a protector panel that is electrically connected to the telecommunications equipment, to the wiring broken out from the cabling, and to ground.
FIGS. 1A-D show views of the end, front, side, and back, respectively, of a conventional protector panel 100 used to provide electrical isolation in a typical telecommunications application. The body 101 of protector panel 100 is made from an insulating material, such as an appropriate insulating plastic. In this particular implementation, protector panel 100 is configured to receive up to 25 five-pin plug-in protectors at 25 different locations. Each location has five holes 102 into which five electrically conducting connectors 104 are inserted and a smaller sixth hole 106 that helps ensure that a plug-in protector is inserted with the correct orientation. Four of the five connectors 104 provide wire-wrap posts on the back side of protector panel 100 for connecting to the cable-side and equipment-side wiring, while the fifth connector 104e forms a loop that is connected (e.g., soldered) to one of a number of grounding bars 108, which in turn are connected (e.g., soldered) to a grounding strip 110.
Grounding bars 108 and grounding strip 110 of protector panel 100 provide the electrical connection between the fifth connector 104e of each plug-in protector location and ground. In order to ensure a good ground connection, protector panel 100 is securely mounted onto other structure (not shown) that provides a good electrical connection between grounding strip 110 and grounded conductors on that other structure. Grounding strip 110 is configured to wrap around one edge 112 of protector panel 100. Protector panel 100 is then bolted onto the other structure using bolts (not shown) that pass through mounting holes 114 in protector panel 100. In order to ensure good electrical connection between grounding strip 110 and the external grounded conductors without damaging the relatively fragile insulating material, electrically conducting spacers 116 are inserted into the mounting holes 114 between the bolt and the grounding strip 110. Each spacer 116 has a lip 118 that ensures that pressure applied by the bolt will result in a secure grounding connection without applying too much pressure to the insulating material.
FIGS. 2A-C show views of the end, front, and side, respectively, of grounding strip 110 of protector panel 100 of FIG. 1. FIGS. 2A-C correspond to the views shown in FIGS. 1A-C. Grounding strip 110 is mounted onto body 101 of protector panel 100 via screw holes 202, while mounting holes 204 align with mounting holes 114 in body 101 for receiving the mounting bolts used to mount protector panel 100 to external structure. Mounting holes 204 in grounding strip 110 have a smaller diameter than mounting holes 114 in body 101 in order to abut and support lips 118 of spacers 116. Grounding strip 110 is typically made by cutting material from a sheet of conducting metal such as aluminum, drilling the mounting and screw holes, and then bending the material 90 degrees at one edge.